Is there any reason for a 7.62x39 improved

[426nut]

Howdy, I'm new to the 7.62x39 caliber and I'm wondering if there would be any viable advantage to have it reamed out to an improved chambering. Thank you, e.

 

[gunsandgunsmithing]

Howdy, I'm new to the 7.62x39 caliber and I'm wondering if there would be any viable advantage to have it reamed out to an improved chambering. Thank you, e.

Kinda...A small 30 cal on a ppc bolt that can run with a 30BR. But, I've been shooting a 30 Major(Grendel) for years now and while the capacity is about equal, the Lapua Grendel brass is way, way better than their(or any that I've found) x39 brass. So not much reason other than x39 brass is cheap and readily available. Just don't hit it hard. The Lapua 6.5 Grendel brass is just as good as their famous 220R brass and is way easier to form. Just a simple neck up from 6.5 to 30.

 

[S11033]

The advantage in my view would be to keep brass more stable. My understanding is that the extreme taper makes the brass life pretty dismal. You could make it a .308 bore to have projectile options while you're at it. I think it would be pretty cool. God I can't wait to have a lathe

 

[msalm]

I ran a 6.5 Grendel reamer into a Howa mini 7.62x39 chamber and made a .311 bore Grendel. It worked well, shooting standard 7.62 ammo (new Starline brass loads) fire formed them nicely. Didn’t get past that stage though and see what performance that slight increase offered. Decent little case though and I was hoping for 2500, maybe 2600 w/ 125gr bullets. Still laying around waiting for me to get back to it.

 

[ebb]

I think for the question to be answered properly you need to tell us if it's a semi auto or a bolt action. Even with my AR10 in 260 on the bench I lose some of the brass. With a bolt action brass would be safe from and overpowered ejector. If I was reasonably sure I was going to load it till he pockets got loose, or the necks split, it would be worth it to me. If shot from an AK or similar and ejected into the next county, it would almost be a one and done and not worth the time.

 

[bozo699]

Howdy, I'm new to the 7.62x39 caliber and I'm wondering if there would be any viable advantage to have it reamed out to an improved chambering. Thank you, e.

For me… No! But that’s the fun thing about this sport….. the sky is just about the limit . If you want one go for it and post your findings.
Wayne

 

[Jason D Hostetter]

Really only worth it, in a true .300/.308, you can still get more velocity, just using a 6.5 Grendel reamer with a 30 cal pilot, and making a 30 Grendel, aka 30 AR, or 30 Major, but the bullet selection in .310/.311 kinda sucks, and .308 bullets will shoot, just not as good as they do in a .308 groove.

 

[Ledd Slinger]

I love the 7.62x39 as it is. Never intended to be a fast round. It was designed to pack a decent punch while being arguably the most reliable round for magazine feeding. I have an AR-15 chambered in 7.62x39 and it will easily punch 1” 5 shot groups at 100 yards while only using a 6x scope and cheap FACTORY brass cased Winchester ammo!!!

Never fails to feed, function, or fire, and it hits with a lot more authority than an 5.56. Absolutely love it over other AR chamber offerings. If you need something faster, chamber for a different round.

 

[gunsandgunsmithing]

I ran a 6.5 Grendel reamer into a Howa mini 7.62x39 chamber and made a .311 bore Grendel. It worked well, shooting standard 7.62 ammo (new Starline brass loads) fire formed them nicely. Didn’t get past that stage though and see what performance that slight increase offered. Decent little case though and I was hoping for 2500, maybe 2600 w/ 125gr bullets. Still laying around waiting for me to get back to it.

Those speeds are easy in a bolt gun and at about max in a 16" AR15 in a 30 Major/Grendel.

On a side note...Do you have to blow the grendel brass out a tad. It's been a long time but was thinking that you'd need to run a grendel reamer in a few thou deep to clean up the x39 but I'm going from memory. It's close, IIRC, but I don't remember how much and...I could be mistaken entirely.

I've done lot of wildcatting on grendel brass. A 30 Major was my first venture with it. Longer story than I have time for, as to how it got the name 30 Major but te original intent was to make Major Power Factor with 125ish gr bullets at a little under 2650fps from a 16" bbl. It did so pretty easily in every bbl I tested. It shot so well, I went with it as a PPC bolt face compatible VFS BR rifle and did quite well with it. It may still hold some records up in Canada. It really will shoot if you use and build with good components. As will the x39, with the right components and rifle. It'll stretch a bit more than a Grendel Cat will but not terribly. The overall capacity is tad more in the 30 Grendel than the x39 but not by much. You might not get 2650 from a gas gun with the 125s but very likely you could.

 

[std7mag]

Ok, since it has been started.
What kind of pressures and volume are we looking at for the -39 improved case?
If we are talking bolt action, why not push the shoulder forward and change the angle to 40°?

Might make an interesting 7mm cartridge for short range Benchrest.